This application claims the priority of German Patent Application Serial No. 199 60 791.5, filed Dec. 16, 1999, the subject matter of which is incorporated herein by reference.
The present invention relates to a lock, in particular a door lock, whose operating handle constantly is in operative connection with a drive member of an electromechanical coupling device, which upon recognition of an authentication code makes an operative connection with a driven member, which in turn constantly is in operative connection with the actuating mechanism of the lock. A lock with an electromechanical coupling device is known from British Pat. No. GB 2,211,239 A. The electromechanical coupling device includes an electromagnet, which is at least partly accommodated in the operating handle. As such locks sometimes must take up considerable operating forces without being damaged, the electromechanical coupling device of the known lock has a correspondingly massive design. It therefore requires much space and a powerful supply voltage source, which excludes a battery operation and thus a retrofittability of the lock without complex laying of supply voltage lines.
A lock of the type described above is known from German pat. No. DE 195 02 288 A1. The drive member and the driven member are disposed collinearly and are designed for rotary actuation. The end faces of drive member and driven member facing each other are designed to produce a complementary positive connection when the driven member is moved from the disengaged into the engaged position. To produce the engaged position, the electro-mechanical transducer, which can be a bistable lifting magnet, must move the driven member and, when the positively connected elements are not aligned, also the drive member against the action of the springs loading these parts into their rest position, by overcoming all frictional forces acting on the force-transmitting members. The transducer therefore has a large size and, like the lock in accordance with the prior art described above, requires a powerful supply voltage source which excludes, for instance, a battery operation.
It is thus an object of the present invention to provide an improved lock, obviating the afore-stated drawbacks.
In particular, it is an object of the present invention to provide an improved lock of the type described above, which requires little volume without a loss in mechanical ruggedness, and which includes an electromechanical coupling device that requires only little electrical power for switching between the disengaged and the engaged position.
These objects, and others which will become apparent hereinafter, are attained in accordance with the present invention by providing a locking mechanism which includes an actuator, which in the disengaged position of the locking mechanism is releasably latched with the drive member and can be moved in the same direction as the drive member, and in the engaged position is blocked in its rest position by means of the electromechanical transducer, with the latching being automatically released upon movement of the drive member, and at least one locking body which is movable in the drive member approximately at right angles to its plane of movement, wherein the actuator has a recess disposed opposite the locking body in the rest position of the parts, and the driven member has a recess which is disposed opposite the locking body, so that in the disengaged position, the driven member in its rest position urges the locking body into the recess of the actuator entrained by the drive member upon movement of the drive member, and in the engaged position, the actuator blocked in its rest position urges the locking body into the recess of the driven member and thereby entrains the driven member, upon movement of the drive member.
To produce the engaged condition, the electromechanical transducer only needs to block the drive member in its rest position, which in any case is spring-loaded in the direction of this rest position. The force required to produce a frictional connection between the drive member and the driven member is produced by the subsequent movement of the drive member itself, i.e. of the user moving the same. Therefore the force-transmitting parts, i.e. primarily the at least one locking body, can be designed according to the maximum force to be expediently transmitted, without the energy demand or the electrical power required by the electromechanical transducer becoming correspondingly high.
Suitably, the releasable latching between the actuator and the drive member includes an engagement part connected with one of the actuator and drive member and engaging in the recess of the other one of actuator and drive member under an elastic bias.
Also contributing to a small demand of electrical energy when the electromechanical transducer in the engaged position brings a locking member into positive engagement with the actuator, in order to block the actuator in its rest position.
An activation of the electromechanical transducer to produce the disengaged position becomes superfluous when in the disengaged position the actuator urges the locking member into the release position when the actuator is entrained by the drive member.
Suitably, the locking body and/or the locking member is a roller or a ball. In the embodiment as roller, greater forces can, of course, be transmitted than in the embodiment as ball. In practice, a plurality of rollers or balls will be used for transmitting the forces, also to avoid jamming of the parts movable with respect to each other.
For simple locks, e.g. wardrobe locks, whose latch or locking bar is actuated without key via a sliding knob, the actuator, the drive member and the driven member can be disposed so as to be linearly movable. The drive member can then be integral with the operating knob, and the driven member can be integral with the latch or the locking bar.
To achieve a compact design, the electromechanical transducer can lie in a plane parallel to the plane of movement of the actuator.
In particular in the embodiment where the door lock has a pawl, the actuator, the drive member and the driven member can be rotatably mounted. This allows the use of a common lock case, which in particular in the case of retrofitting or conversion of existing door locks to a keyless operation, e.g. by means of a code card or a transponder, is of great advantage.
According to another feature of the present invention, the actuator, the drive member and the driven member may be formed by rings with a common axis of rotation. In this case, the ring-shaped drive member is suitably positively connected with a first square for mounting the operating handle, and the ring-shaped driven member is frictionally connected with a second square for actuating the nut of a common door.
To achieve a small building depth, the ring-shaped driven member, the ring-shaped drive member and the ring-shaped actuator can substantially be arranged concentric with respect to each other, with their confronting peripheral surfaces cooperating with one another.
It is also favorable for a small building depth when the electromechanical transducer is disposed approximately in the same radial plane as the ring-shaped actuator and preferably parallel to a line which is tangent to the periphery of the actuator.
On the other hand, when the diameter should be minimized, it may be suitable to line up the ring-shaped driven member, the ring-shaped drive member and the ring-shaped actuator substantially co-linear axially succeed each other substantially collinearly in succession in axial direction, with their confronting end faces cooperating with each other.
To achieve a small diameter, it is also useful when the electromechanical transducer lies in a radial plane, which is offset in parallel to the radial plane in which the ring-shaped actuator is disposed.
The electromechanical transducer can, in particular, be an electric mini- or micro-motor, which may be configured in a manner known per se as a threaded spindle motor or is coupled downstream thereof with a corresponding transmission for converting the rotating movement into a translational movement of a spindle or a pin, which in turn acts on the locking member.
However, the electromechanical transducer preferably includes a bistable lifting magnet with an armature and an armature rod which acts on the locking member. The armature and thus the armature rod of such a lifting magnet are normally held in the one end position by a spring and in the other end position by a permanent magnet. For switching between the two end positions short current pulses of opposite signs are sufficient. In this case, the demand of electrical energy for switching the lock between the disengaged position and the engaged position (and vice versa) is extremely small.
The demand of electrical energy for the proposed lock can be satisfied by means of a battery. A configuration of the electromechanical transducer as bistable lifting magnet leads to a particularly long service life of the battery.